The University of Wisconsin sent out letters to roughly 60,000 students and staff, warning that hackers had managed to breach a campus ID database containing names, social security numbers and other sensitive information, reports the eSecurity Planet.

According to the letter, the hackers had unlimited access to the database for more than two years, going back as far as January 2008. School officials said there have not been any signs of any student or staff information being used for malevolence purposes.

“The University apologizes to you for this situation,” the advisory letter said. “We take computer and data security very seriously, making consistent and strong efforts to protect thousands of computers located on the campus.”

The said it has reviewed all security procedures and policies and deployed network intrusion detection applications and implemented a vulnerability identification program to better safeguard student and staff data.